Towing systems and methods using magnetic field sensing

Abstract

A magneto-elastically-based active force sensor, used with a tow coupling between a towed and a towing vehicle or a coupling between a vehicle body and a suspension of the vehicle, which outputs a signal useful for determining forces acting on the coupling. The outputted force information may be provided by processor-enabled embedded software algorithms that take inputs from the force sensor and other sensors, may be used by one or more vehicle systems during operating of the vehicle, such as engine, braking, stability, safety, and informational systems. The force sensor includes directionally-sensitive magnetic field sensing elements inside the sensor, and shielding may be used around the sensors to reduce the influence of external magnetic fields on the sensing elements. The force sensor may be used with different tow and vehicle weight sensing coupling devices installed on different types of automobile cars and trucks.

We claim: 
     
       1. A height-adjustable tow hitch apparatus comprising:
 a vehicle coupler having a connection point adapted for connecting to a trailer vehicle; 
 a towing vehicle coupler having a portion adapted for connecting to a towing vehicle; 
 a coupler part for connecting the vehicle coupler to the towing vehicle coupler at one of a plurality of different vertical positions relative to the towing vehicle; 
 at least two load sensor pins; and 
 a portable computing device having a display, 
 wherein the vehicle coupler comprises at least an upper and a lower bracket, each bracket having a through-hole for receiving respective ones of the at least two load sensor pins, 
 wherein the coupler part optionally comprises through-holes for receiving at least one fastening pin inserted in the through-holes, and 
 wherein the at least two load sensor pins are adapted to outputting an electrical signal to the portable computing device indicative of a force when a force is applied to the connection point. 
 
     
     
       2. The tow hitch apparatus of  claim 1 , wherein the coupler part further comprises left and right side walls, each side wall having upper and lower through-holes corresponding to the upper and lower bracket through-holes for receiving respective ends of the at least two magnetoelastic load sensor pins. 
     
     
       3. The tow hitch apparatus of  claim 1 , wherein the at least two load sensor pins each comprise:
 an elongated generally cylindrically hollow and elastically deformable shaft having at least one magneto-elastically active region directly or indirectly attached to or forming a part of the shaft at an axial location spaced from one end of the shaft, wherein the at least one active region possesses a remanent magnetic polarization; and 
 at least one printed circuit board processor, the processor being adapted to receiving signals from at least one magnetic field sensor device arranged proximate to the at least one magneto-elastically active region, wherein the at least one magnetic field sensor device includes at least one direction-sensitive magnetic field sensor configured for determination of a shear force in at least one direction, wherein the at least one printed circuit board processor and the at least magnetic field sensor device are arranged to have a predetermined and fixed spatial position inside the hollow shaft. 
 
     
     
       4. The tow hitch apparatus of  claim 3 , further comprising two magneto-elastically active regions directly or indirectly attached to or forming a part of the shaft at longitudinally spaced apart locations from respective ends of the shaft, wherein each of the two active regions possess a remanent magnetic polarization. 
     
     
       5. The tow hitch apparatus of  claim 1 , further comprising a storage or memory device containing software for computing the amount and direction of force acting on the connection point, wherein the storage or memory device is arranged inside the hollow shaft or in an external module. 
     
     
       6. The tow hitch apparatus of  claim 1 , wherein the portable computing device is adapted to displaying one or more of a numerical, textual, and indicia information about the force acting on the connection point. 
     
     
       7. The tow hitch apparatus of  claim 1 , further comprising a shielding device positioned around all or a portion of the at least two load sensing pins for reducing the strength of an external magnetic field at a detecting region of the at least one direction-sensitive magnetic field sensor. 
     
     
       8. The tow hitch apparatus of  claim 1 , further comprising at least one secondary magnetic field sensor arranged to have a predetermined and fixed spatial position inside the hollow shaft for outputting a secondary signal, wherein the secondary signal contains information about external magnetic fields at a detecting region of the at least one direction-sensitive magnetic field sensor. 
     
     
       9. The tow hitch apparatus of  claim 1 , wherein the through-hole of the upper bracket or the through-hole of the lower bracket has an oval shape to provide a gap between the wall of the through-hole and the surface of the at least one load sensor pin inserted therein thereby providing a movement degree of freedom to the at least one load sensor pin in the through hole. 
     
     
       10. The tow hitch apparatus of  claim 1 , wherein one of the at least two load sensor pins is adapted to measuring the force applied to the connection point in at least a longitudinal direction of the tow hitch apparatus. 
     
     
       11. The tow hitch apparatus of  claim 10 , wherein the one of the at least two load sensor pins is adapted to measuring the force applied to the connection point in the longitudinal direction and in a direction that is transvers to the longitudinal direction. 
     
     
       12. A computer-implemented force measuring method comprising:
 attaching a height-adjustable tow hitch apparatus to a towing vehicle, the tow hitch comprising at least one magneto-elastically active region, at least one magnetic field sensor device, and a communications device for wirelessly connecting to a portable computing device; 
 initializing a communication between the at least one magnetic field sensor device and the portable computing device; 
 receiving one or more signals from the at least one magnetic field sensor device having information about a magnetic field generated by the at least one magneto-elastically active region; 
 connecting a towing vehicle to the tow hitch apparatus; 
 computing a force value when a force is applied to the tow hitch apparatus using the one or more signals, wherein computing the force value includes computing a total tongue weight on a connection point of the tow hitch apparatus; and 
 displaying the force value or an information about the force value on the portable computing device. 
 
     
     
       13. The method of  claim 12 , wherein the height-adjustable tow hitch apparatus comprises at least two load sensor pins each comprising:
 an elongated generally cylindrically hollow and elastically deformable shaft having at least one magneto-elastically active region directly or indirectly attached to or forming a part of the shaft at an axial location spaced from one end of the shaft, wherein the at least one active region possesses a remanent magnetic polarization; and 
 at least one printed circuit board processor, the processor being adapted to receiving the one or more signals from at least one magnetic field sensor device arranged proximate to the at least one magneto-elastically active region, wherein the at least one magnetic field sensor device includes at least one direction-sensitive magnetic field sensor configured for determination of a shear force in at least one direction, wherein the at least one printed circuit board processor and the at least magnetic field sensor device are arranged to have a predetermined and fixed spatial position inside the hollow shaft. 
 
     
     
       14. The method of  claim 12 , wherein the step of computing a force value using the one or more signals includes computing one or more of a longitudinal force, a vertical force, and a transverse force measured at the connection point. 
     
     
       15. The method of  claim 12 , wherein each of the at least two load sensor pins comprises two magneto-elastically active regions directly or indirectly attached to or forming a part of the shaft at longitudinally spaced apart locations from respective ends of the shaft, wherein each of the two active regions possess a remanent magnetic polarization. 
     
     
       16. The method according to  claim 12 , further comprising:
 after computing a force value when a force is applied to the tow hitch apparatus using the one or more signals, automatically or manually setting each of the signals to zero. 
 
     
     
       17. The method of  claim 12 , further comprising:
 receiving a signal from a magnetometer device representing an amount of an external magnetic field when an external magnetic field is present at a detection region of the at least one magnetic field sensor device.